1. Field of the Invention
The present invention relates to apparatus which is used for measuring the constituents in the combustion exhaust gas effluent of a fossil-fired steam generator or boiler system. More particularly, the invention relates to an apparatus which measures with extreme accuracy the concentrations of CO.sub.2 and superheated water as produced from the fossil fuel combustion process so that the fuel flow and thermal efficiency of fossil-fired systems can be determined by thermodynamics for monitoring the operation of such a system.
The importance of accurately determining thermal efficiency is critical to the thermal performance monitoring of any fossil-fired system. If practical day-to-day improvements in efficiency are to be made, and/or corrections to thermally degraded equipment are to be found and corrections taken, then accuracy in determining thermal efficiency is an obvious necessity. The art of tracking the efficiency of a conventional power plant or any fossil-fired system lies fundamentally in measuring the useful output and the total energy flow of the input fuel.
The art of measuring the useful output of a conventional fossil-fired system is highly developed. The useful output can be either the steam flow produced or the subsequent electrical power generated via, commonly, steam expansion in turbines. Measuring the total energy flow of the input fuel, on the other hand, has traditionally caused significant problems, especially for coal-fired power plants. Measurement of the energy flow of the input fuel requires knowledge of the heating value of the fuel and its mass flow rate.
The present invention is specifically designed for the purpose of measuring the combustion effluent with extreme accuracy whereby the mass flow rate of the input fuel can be thereby calculated from thermodynamics without direct measurement of the input fuel flow rate. The embodiment of the invention is called an "Emissions Spectral Radiometer/Fuel Flow" instrument, or ESR/FF instrument.
2. Description of the Prior Art
Present industrial techniques for measuring or analyzing the composition of combustion effluent of a fossil-fired system include: sampling the gas and analyzing with gas chronography (for CO, CO.sub.2, and O.sub.2 and unburned hydrocarbons); sampling the gas and analyzing using spectrographic absorption of ultraviolet or infrared radiation (for CO, CO.sub.2, H.sub.2 O, O.sub.2 and unburned hydrocarbons); sampling the gas and reacting it with certain chemicals which thus determines concentrations (for CO.sub.2, O.sub.2 and other gases); in-situ detection of O.sub.2 by zirconium hydride; and in-situ spectrographic absorption of ultraviolet or infrared radiation (for CO, CO.sub.2, H.sub.2 O, O.sub.2 and unburned hydrocarbons). All of these techniques have been in general industrial use for many years. All known techniques involve obtaining samples of the combustion gas and its subsequent analysis in a laboratory environment, except use of in-situ spectrographic absorption techniques and the use of zirconium hydride for O.sub.2 detection.